Sealable containers

ABSTRACT

The present invention relates to containers and methods suitable for uses such as liquid hot-fill processes. More specifically the invention relates a containers having gas permeable vents with an integral sealing means that is externally activatable by non-mechanical means to effect hermetic sealing of the containers after filling.

RELATED APPLICATION DATA

This application is a divisional of co-pending U.S. application Ser. No.12/404,247, filed Mar. 13, 2009, which claims priority under 35 U.S.C.§119(e) to U.S. Provisional Application Ser. No. 61/069,377 filed Mar.15, 2008.

FIELD OF THE INVENTION

The invention relates to sealable containers and sealing methods andmore particularly to containers and methods for hot-filling beverages.

BACKGROUND

In the packaging industry many factors drive the use of plasticcontainers and closures for various applications including hot-fillapplications. Such factors include the continuing migration of beveragepackaging as well as other packaging from glass containers to plasticcontainers, the increasing use of single-serve sizes and theproliferation of juice drinks, nectars, energy drinks and othernutritious beverages. The hot-fill process is essentially a packagingprocess employed to extend shelf life of the product. Such packagingsystems allow products containing even highly perishable ingredientssuch as milk to be stored without refrigeration for extended periods.Efficient closures are the first line of defense against microbialcontamination that would compromise that product shelf life, howeverclosures have been one of the most difficult aspects of totally plasticpackaging to incorporate into filling applications such as hot-fillsystems. In current beverage hot-fill processing, vacuum develops in thecontainer as a result of cooling of headspace gases in a hermeticallysealed closure/container system. The ensuing pressure differential isoften strong enough to cause severe container deformation, which isunacceptable to the consumer. To avoid such deformation most plasticbeverage bottles are designed with greater thicknesses and collapsiblepanel geometries to accommodate the volume changes caused by internalvacuum formation. As a result, these dedicated hot-fill beveragecontainers are significantly more expensive compared to sterile-fill andother containers due to the increased plastic material required fortheir fabrication. Also, as closure designs are refined, bottlers have35 the option of eliminating process steps to make operations moreefficient and less costly. Newer hot-fill closure systems that alleviatehot-fill limitations are being designed. For example, the PCTapplication published as WO 2006/053013 to Trude et al. describes a sealwith a physically moveable portion useful for hot-fill and pasteurizablebottles. The moveable portion of the seal moves in response to pressurecreated in a container during the processes of hot-fill andpasteurization and accommodates changes in pressure within the containerand prevents ambient air from passing into the container.

United States Patent Application 2004/0265447 to Raniwala describes amethod of hot-filling a plastic bottle wherein the bottle is providedwith an air permeable membrane-covered hole 45 used to equalize pressurebetween the interior of the container and the ambient pressure as thebottle and contents cool, after which a seal is mechanically andindependently applied over the membrane-covered hole. However, since thesealing means is not an integral part of the device and requires amechanical step the method does not readily lend itself to an overallautomated and rapid hot-filling process. U.S. Pat. No. 7,143,568 to VanHeerden et al. discloses a method for sealing a container that includesa crushable material that is mechanically deformed to effect a seal.Since, such a method does not provide gas venting of the container itnot applicable to the filling applications addressed by the containersof the present invention.

Therefore, a need exists for improved methods and container for hot-fillprocesses wherein a vented container also have an integral capability toself-seal via non-contact or direct contact means, rendering thecontainer system hermetically sealed at the conclusion of the fillingprocess.

A need also exists for improved sealable, vented retort pouches forpackaging a variety of perishable foodstuffs.

A further need exists for sealable, vented containers that arepressurizable with a gas such as nitrogen or carbon dioxide prior tosealing.

A still further need exists for sealable, vented containers having avisual indicator activated by the sealing process, wherein the indicatorshows that the container has been sealed.

The devices and methods of the present invention address these and otherneeds.

SUMMARY OF THE INVENTION

The present invention provides sealable containers suitable for usesincluding, but not limited to, liquid hot-fill processes. The containercomprises a container body which is formed by a wall defining andseparating an interior space from the exterior environment, wherein thecontainer body has at least one a closable opening; a container closuremeans mated to the closable opening and a gas permeable vent componentproviding gaseous communication between the interior space of thecontainer body and the exterior environment, wherein the vent componentcomprises a vent component sealing element that is externallyactivatable to effect hermetic sealing of the container. Such externalactivation is non-mechanical and requires only radiative contact withthe sealing elements and/or components of the container. In certainpreferred embodiments the gas permeable vent component is disposedwithin the container closure means while in other preferred embodimentsthe gas permeable vent component is disposed within in the wall of thecontainer body. In certain embodiments the gas permeable vent componentis a porous matrix or porous membrane, which can be hydrophobic,hydrophilic, oleophobic or oleophilic. In certain embodiments the porousmatrix is fabricated from a polymer such as a polyolefin or fluorinatedpolyolefin. A list of suitable polyolefins includes, but is not limitedto, polyethylenes polypropylenes, ethylene/propylene copolymers,polybutylenes, polymethylpentenes, copolymers thereof and combinationsthereof. A particularly suitable fluorinated polyolefin ispolytetrafluoroethylene, which is readily avoidable in the form of aporous matrix or porous membrane. In certain other embodiments theporous matrix or membrane is fabricated from ethylene copolymersincluding, but not limited to, ethylene/vinyl acetate copolymers,ethylene/vinyl alcohol copolymers and polyvinyl acetates as well asalloys, mixtures and combinations thereof.

In certain embodiments the porous matrices or porous membranes of thevent components have a pore diameter range of 1 μm to 350 μm with 5 μmto 40 μm being preferred. While in certain other embodiments the porousmatrices or porous membranes of the vent components have a pore diameterranging from 0.01 μm to 5.0 μm with 0.05 μm to 2.0 μm preferred and 0.10μm to 0.20 μm most preferred.

In certain embodiments the vent component sealing composition is aporous fusible material, which in certain embodiments is disposeddirectly above or below the porous matrix and in certain preferredembodiments is in intimate contact with the porous matrix. In certainother embodiments the vent component has a laminate structure whereinthe vent component sealing composition is disposed between a firstporous matrix and a second porous matrix. In certain embodiments theporous fusible material is a thermoplastic and in certain preferredembodiments such a thermoplastic is a hot-melt adhesive, which incertain embodiments comprises an energy absorbing material such as ametal or other such adhesive activator. In some embodiments the energyabsorbing material is an electrically conductive metallic material andin certain preferred embodiments such a metallic material comprisesiron, steel, aluminum, titanium, zinc, copper or silver. In certainembodiments wherein the porous fusible material comprises a metal ormetallic composition the sealing element is externally activatable by anelectromagnetic induction source operating at a frequency ranging from 5kHz to 100 GHz. In certain preferred embodiments the fusible sealingelement is externally activatable by an electromagnetic induction sourceoperating at a frequency ranging from 5 kHz to 900 MHz. In yet certainother preferred embodiments the fusible sealing element is externallyactivatable by an electromagnetic induction source operating at afrequency ranging from 800 MHz to 100 GHz.

In certain embodiments the metallic composition is in the form of aporous metal foil and the sealable container of has a laminate structurecomprising a vent fusible sealing composition, a first porous matrix, asecond porous matrix and a porous metal foil disposed such that thefusible sealing composition is in intimate contact with the porous metalfoil. In certain other embodiments the metal or metallic composition isin the form of a thin coating deposited on a suitable porous film, whilein yet other embodiments the energy absorbing metal is in the form ofmacroparticles or microparticles dispersed throughout the porous fusiblematerial.

In certain embodiments the vent component sealing composition comprisesan adhesive composition curable by exposure to ultra violet (UV)radiation, wherein such an adhesive composition is cured by aphotochemical reaction. In still other embodiments the vent componentsealing composition comprises an adhesive curable by electron beam (EB)radiation. Also provide by the present invention is a method forhot-filling and sealing a container comprising the steps of: providing acontainer as herein described; filling the container with hot liquid;allowing the liquid to cool to desired degree and then externallyactivating the vent component sealing composition by non-mechanicalmeans to effect hermetic sealing.

The art described herein is not limited to filling applications and canbe applied to any container application that requires a self-sealingvent disposed within any surface of the container including the closure.Applications may also include venting, venting and sealing, vacuum andsealing and pressurization sealing as well as lyophilization andsealing. Additional applications may include venting after sealing aswell by using reversible sealing mechanisms such as pull tabs, removableplugs and meltable seals that can be removed from vent areas bymechanical means, capillary absorption into adjacent materials,application of pressure or vacuum, and/or thermal means. A suitablecontainer may or may not contain a discreet closure component. Forexample a plastic, glass or metal bottle typically contains a cap orclosure on top. A retort pouch or bag may be sealed completely but notnecessarily contain a cap or closure. In addition a closure can be anyattached component or part of a container used to cap, seal, encapsulateor gain access to the contents of said container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an isometric view of an embodiment of a sealablecontainer wherein a sealable vent component is disposed within thecontainer cap.

FIG. 2 depicts an isometric view of an embodiment of a sealablecontainer wherein a sealable vent component is disposed within thecontainer wall.

FIG. 3 depicts a sectional frontal orthographic view of an embodimentwith a sealable vent component disposed within a threaded container cap.

FIG. 4 depicts a sectional frontal orthographic view of an embodimentwith a sealable vent component disposed within a threaded container cap.

FIG. 5 depicts a sectional frontal orthographic view of an embodimentwith a sealable vent component disposed within a threaded container cap.

FIG. 6 depicts a sectional frontal orthographic view of an embodimentwith a sealable vent component disposed within a wall of a containerbody.

FIG. 7 depicts a sectional frontal orthographic view of an embodimentwith a sealable vent component disposed within a wall of a containerbody.

FIG. 8A depicts a sectional frontal orthographic view of a sealable ventcomponent disposed within a threaded container cap positioned within therange of an induction heating means at the onset of induction heating.

FIG. 8B depicts a sectional frontal orthographic view of a sealable ventcomponent disposed within a threaded container cap after sealing with aninduction heating means.

FIG. 9 depicts an isometric view of an annular sealable vent elementdisposed within a threaded container cap.

FIG. 10 depicts an orthographic sectional view of annular sealable ventelement disposed within a threaded container cap.

FIG. 11 depicts an exploded isometric view of an embodiment of asealable container wherein an annular sealable vent component isdisposed within the container cap.

FIG. 12 depicts a sectional orthographic frontal view of the containercap of the embodiment of depicted in FIG. 11.

Although the figures presented herein illustrate some preferredembodiments, they are intended to be merely exemplary and representativeof certain embodiments. To that end, several figures contain optionalfeatures that need not be included in any particular embodiment of theinvention. Furthermore, the shapes, types, or particular configurationsof the various elements of the illustrated devices should not beregarded as limiting to the invention.

DETAILED DESCRIPTION

For the purposes of the invention described in this application, certainterms shall be interpreted as shown below.

Fusible materials are materials that either melt or soften upon theapplication of heat and re-solidify or re-harden upon subsequentcooling.

Induction heating is a non-contact heating process wherein anelectrically conducting material is heated by electromagnetic inductionvia eddy currents generated within the conducting material and whereinelectrical resistance effects to Joule heating. An induction heater forany process consists of an electromagnet through which a high-frequencyalternating current (AC) is passed. Heat may also be generated bymagnetic hysteresis loss in materials that have significant relativepermeability. The frequency of AC used depends on factors such as theobject volume, specific material type, coupling distance between theelectromagnet and the material to be heated and the desired penetrationdepth.

Macroporosity refers to the overall void volume of a material andclassifies individual pores that are considered large in size and have apore diameter >0.050 μm as classified according to the InternationalUnion of Pure and Applied Chemistry (IUPAC) Subcommittee ofMacromolecular Terminology, definitions of terms drafted on Feb. 26,2002.

Microporosity refers to the individual pore sizes or distribution ofpore sizes that constitute the microstructure of a porous material andclassifies individual pores that are considered small in size and have apore diameter <0.002 μm as classified according to the InternationalUnion of Pure and Applied Chemistry (IUPAC) Subcommittee ofMacromolecular Terminology, definitions of terms drafted on Feb. 26,2002.

Mesoprosity refers to the individual pore sizes or distribution of poresizes that constitute the microstructure of a porous material andclassifies individual pores that are considered medium in size and havea pore diameter between 0.002 to 0.050 μm as classified according to theInternational Union of Pure and Applied Chemistry (IUPAC) Subcommitteeof Macromolecular Terminology, definitions of terms drafted on Feb. 26,2002.

Void volume of a material is synonymous with percent porosity.

Certain embodiments of the devices and processes of present inventionprovide means for the efficient hermetic sealing of containers, whileother embodiments provide means for partial sealing and/or reversiblesealing of containers. Various embodiments of devices of the presentinvention comprise venting orifices; venting seals; venting conduitssuch as holes; channels and threads; as well as porous matrices andporous membranes. The porous membranes can be microporous, mesoporous ormacroporous. The sealing can be effected by a variety of meansincluding, but not limited to, physical contact, compression, spinwelding, electrical induction, electrical current, electromagneticradiation, heating with a hot probe, ultrasonic radiation, infraredradiation, laser beams and the like. A variety of materials are usefulfor creating the seal in sealing devices of the present inventionincluding, but is not limited to, adhesives, glues, hot melts, waxes,thermoplastics, thermoplastic elastomers and the like. The extent ofsealing as well as the reversibility of the seal depends upon thepenetration of the seal material into the other materials comprising thedevice as well as to the degree of chemical or physical bonding of theseal material into the other materials comprising the device.

Sterilization of the vent areas prior to, during or after sealing can beeffected by a variety of standard sterilization processes including butnot limited to, thermal, ultra-violet irradiation, electron beamirradiation gamma-irradiation, beta-irradiation, bactericides, chemicalsterilants/disinfectants such as hydrogen peroxide and the like.

Certain embodiments of the present invention are applicable to beveragehot fill processes. In a typical process, following hot filling of ahermetically sealed closure/container system a vacuum exists within thecontainer as a result of headspace cooling. The ensuing vacuum is strongenough to cause severe container deformation of the container, which isunacceptable to the consumer. To avert this problem most plasticbeverage bottles are designed with heavier wall thicknesses andcollapsible panel geometries to accommodate the volume changes caused byinternal vacuum formation. As a result, these dedicated hot-fillbeverage containers are significantly more expensive compared tosterile-fill and other containers due to increased plastic materialusage and special container designs.

Certain embodiments of the present invention are applicable to liquidfill processes wherein the liquid filled container is pressurized viathe vent components prior to sealing. In certain embodiments additionpressurization with an inert gas such as nitrogen, carbon dioxide andthe like is utilized to provide additional container integrity (furtherreducing plastic usage) and to provide enhanced inertness for beverageflavor preservation and extended shelf life. In alternate applicationsvacuum or combinations of vacuum followed by pressurization are appliedto the filled container before sealing to completely remove any tracesof air, oxygen, water vapor or other undesired gases or volatile fluidsprior to sealing.

Embodiments of the present invention employ a sealable, vented closureand obviate the need for traditional bulky hot-fill bottles. In certainpreferred embodiments a sealable container for liquids consists of acontainer body, which is formed by a wall, wherein the container bodyhas a closable opening and a container closure cap mated to the closableopening; a gas permeable vent component providing gaseous communicationbetween the interior of the container body and the exterior environment,wherein the vent component comprises a vent component sealing elementwhich is externally activatable by non-mechanical means to effectsealing such that the gas permeable vent component becoming gasimpermeable. In certain embodiments of such a sealable container the gaspermeable vent component is disposed within in the container closure,while in other embodiments the gas permeable vent component is disposedanywhere within the container body.

Suitable materials for the fabrication of elements of the containerbody, container closures and/or gas permeable vent components of thepresent invention include a wide variety of materials, including, butnot limited to, glasses, ceramics, metals, polymers and waxes as well ascombinations thereof. Such combinations may be intimate combinationssuch as those obtained by blending of two or more components orlaminates of two or more materials. Suitable waxes include natural plantand animal waxes, waxes produced by purification of petroleum andcompletely synthetic waxes as well as mixtures and combinations thereof.

Suitable polymers include rigid plastics, flexible plastics,thermoplastics, thermoset elastomers and thermoplastic elastomers aswell as mixtures and combinations thereof. Suitable thermoplasticsinclude polyolefins and particularly useful polyolefins includepolyethylenes such as low-density polyethylene (LDPE), linearlow-density polyethylene (LLDPE), medium-density polyethylene (MDPE),high-density polyethylene (HDPE) and ultra-high molecular weightpolyethylene (UHMWPE). Other useful polyolefins include polypropylenes(PP), ethylene/propylene copolymers, polybutylenes, polymethylpentenes(PMP), ethylene/vinyl acetate copolymers (EVA), ethylene/vinyl alcoholcopolymers (EVOH) and polyvinyl acetates as well as copolymers, mixturesand combinations thereof.

Other suitable thermoplastics are polyesters including, but are notlimited to, polybutylene terephthalates (PBT); polyethyleneterephthalates (PET), glycol modified polyethylene terephthalates(PETG), polylactides and polycarbonates as well as copolymers, mixturesand combinations thereof.

Still other suitable thermoplastics are polyethers including, but notlimited to, polyalkylene glycols, ethylene glycols, polypropyleneglycols, polybutylene glycols, polyetheretherketone (PEEK), polyacetalsand cellulosics as well as copolymers, mixtures and combinationsthereof.

Still other suitable polymers are vinyl polymers including, but notlimited to, polystyrenes (PS), polyacrylonitrile (PAN),poly(acrylonitrile-butadiene-styrene) (ABS),poly(acrylonitrilestyrene-acrylate) (AES),poly(acrylonitrile-ethylene-propylene-styrene) (ASA), polyacrylates,polyacrylates, polymethacrylates, polymethylmethacrylate (PMMA),polyvinylchloride (PVC), chlorinated polyvinyl chloride (CPVC),polyvinyl dichloride (PVD), polyvinylidene chloride (PVDC), fluorinatedethylene propylene copolymer (FEP), polyvinyl fluoride (PVF),polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) andpoly(ethylene tetrafluoroethylene) (ETFE) as well as copolymers,mixtures and combinations thereof.

Other suitable polymers include, but are not limited to, polyamides suchas nylon 6 and nylon 12, polyimides, polysulfones and polyethersulfones(PES) as well as copolymers, mixtures and combinations thereof.

Suitable thermoset elastomers include, but are not limited to,styrene-butadiene copolymers, polybutadienes, ethylene-propylene rubber(EPR), acrylonitrile-butadiene (NBR), polyisoprene, polychloroprene,silicone rubbers, fluorosilicone rubbers, polyurethanes, hydrogenatednitrile rubber (HNBR), polynorborene (PNR), butyl rubber, halogenatedbutyl rubber, such as chlorobutyl rubbers (CIIR) and bromobutyl rubbers(BIIR), commercially available fluoroelastomers such as Viton™, Kalrez™and Fluorel™ and chlorosulfonated polyethylene as well as copolymers,mixtures and combinations thereof.

Suitable thermoplastic elastomers (TPE) include, but are not limited to,thermoplastic polyolefins (TPO) including those commercially availableas DEXFLEX™ and INDURE™; elastomeric polyvinyl chloride blends andalloys such as ALCRYN™; styrenic block copolymers includingstyrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS),styrene-isobuytlenestyrene (SIBS), styrene-ethylene/butylene-styrene(SEBS), and styrene-ethylene-propylenestyrene (SEPS), some of which arecommercially available as KRATON™, DYNAFLEX™ and CHRONOPRENE™;thermoplastic vulcanizates (TPV), also known as dynamically vulcanizedalloys, including those commercially available as VERSALLOY™,SANTOPRENE™ and SARLINK™; thermoplastic polyurethanes (TPU), includingthose commercially available as CHRONOTHANE™, VERSOLLAN™ and TEXRIN™,copolyester thermoplastic elastomers (COPE), including thosecommercially available as ECDEL™; and polyether block copolyamides(COPA) including those commercially available as PEBAX™, as well ascopolymers, mixtures and combinations thereof.

Metals suitable for use in components of certain embodiments of thepresent invention include, but are not limited to, stainless steels,aluminum, zinc, copper, and silver as well as alloys, mixtures andcombinations thereof. Glass and ceramic materials suitable for use incertain embodiments of the present invention include, but are notlimited to, quartz, borosilicates, aluminosilicates and sodiumaluminosilicates. In certain preferred embodiments glass and ceramicmaterials are in the form of sintered particles or fibers. A usefulprocess for fabrication of macroporous plastics useful in embodiments ofthe present invention is sintering, wherein particulate (powdered orgranular) thermoplastic polymers are subjected to the action of heat andpressure to effect partial agglomeration of the particles resulting information of a cohesive porous structure. Such porous material comprisesa network of interconnected pores that form a random tortuous paththrough the structure. In such porous structures, the void volume orpercent porosity is about 1 to 85% depending on the specific conditionsof sintering. In certain embodiments a void volume or percent porosityrange of 30 to 65% is preferred. Variations in material properties suchas surface tension permits such porous materials can be tailored torepel or absorb liquids while permitting passage of air and other gases.U.S. Pat. No. 3,051,993 to Goldman, herein incorporated by reference inits entirety, describes a sintering process for making a porouspolyethylene material.

In certain embodiments the porous matrix or porous membrane of the gaspermeable vent component is by design fabricated from a material that isintrinsically hydrophobic, hydrophilic, oleophobic or oleophilic. Incertain other embodiments the porous matrix or porous membrane of thegas permeable vent component is rendered hydrophobic, hydrophilic,oleophobic or oleophilic by surface treatments, including but notlimited to, chemical treatment, plasma discharge, vapor deposition andthe like. Porous plastic materials suitable for certain embodiments ofthe porous vent components of the present invention are commerciallyavailable in sheets or molded forms under the trademark POREX™ fromPorex Corporation (Fairburn, Ga., U.S.A.). The average porosity of suchPOREX™ materials can vary from about 1 to 350 microns depending on thesize of polymer granules used and the conditions employed duringsintering. Suitable porous plastic materials with pore sizes rangingfrom 5 to 1000 microns are available from the GenPore division ofGeneral Polymeric Corporation (Reading, Pa.) while porous plasticmaterials with pore sizes ranging from 5 to 200 microns are availablefrom MA Industries Inc. (Peachtree City, Ga.) as VYON™. OtherManufacturers of porous plastic materials suitable for certainembodiments of the sealable vent components of the present inventionavailable as SINTERFLO™ from Porvair Technology Ltd (Wrexham NorthWales, U.K.). The size, thickness and porosity of porous vent elementsnecessary for the various embodiments of the present invention may bedetermined by determining the quantity of fluid required to pass throughthe vent over time (flow rate) in a given application. The flow rate fora given area of vent is also known as the flux rate. The flow or fluxrates of a given porous plastic vary and depend on factors includingpore size, percent porosity and cross sectional thickness of the vent.Flow rates are generally expressed in terms of volume per unit timewhile flux rates are generally expressed in terms of fluid volume perunit time per unit area. Therefore, the flow rate or flux rate requiredfor the specific process to which it is applied. For example in asealable vent component of the present invention used in a hot-fillprocess, the flow rate is chosen to be sufficient to permit theequalization of pressure between the container interior and the ambientatmosphere during cooling of the container after hot filling.

In certain embodiments the porous matrices or porous membranes of thevent components have a pore diameter range of 1 μm to 350 μm with 5 μmto 40 μm being preferred. While in 400 certain other embodiments theporous matrices or porous membranes of the vent components have a porediameter ranging from 0.01 μm to 5.0 μm with 0.05 μm to 2.0 μm preferredand 0.10 μm to 0.20 μm most preferred.

In certain preferred embodiments the gas permeable vent component is aporous matrix or membrane with a pore size sufficient to exclude commonbacteria. Such an arrangement permits venting of the container, whichprevents vacuum formation, while providing a sterile microbiologicalbarrier from the manufacturing atmosphere. In such embodiments a porousmatrix or membrane with a pore size less than 0.50 microns is preferredand a porous matrix or membrane with a pore size less than 0.25 micronsis most preferred. However, in such embodiments it is not necessary thatthe porous matrix have a bacteria excluding pore size throughout itsthickness but rather it is sufficient that either the surface of theporous matrix exposed to the interior of the container body or thesurface of the porous matrix exposed to the exterior environment has apore size sufficient to exclude bacteria. Such an arrangement can beachieved by fabrication of porous matrix or membrane as a laminatestructure wherein one or both surfaces have a layer of a bacteriaexcluding pore size material and the core portion of the matrix can havea greater pore size to facilitate venting.

Useful as vent component sealing compositions in embodiments of thepresent invention, are a variety of commercially available hot meltadhesives that are currently used in a wide range of manufacturingprocesses. In general, such hot melt adhesives are solvent-freeadhesives, that are solid at temperatures below about 180° F., are lowviscosity fluids above about 180_(i)F and that rapidly set or solidifyupon cooling. Hot melt adhesives particularly useful for embodiments ofthe present invention include, but are not limited to, paraffin waxes,ethylene vinyl acetate (EVA) copolymers, styrene-isoprene-styrene (SIS)copolymers, styrene-butadiene-styrene (SBS) copolymers, ethylene ethylacrylate copolymers (EEA) and the like, as well as mixtures andcombinations thereof. Often these polymers do not exhibit the full rangeof performance characteristics required for a hot melt adhesiveapplication and a variety of performance enhancing materials such astackifying resins, waxes, antioxidants, plasticizers, and the like othermaterials are added to the adhesive formulation to enhance performance.Other thermoplastic adhesives useful in embodiments of the presentinvention are known as polyurethane reactive (PUR) adhesives. Such anadhesive composition contains a solid one-component urethane prepolymerthat behaves like a standard hot melt wherein it reacts withadventitious moisture to effect crosslinking or chain extension to forma new polyurethane polymer. Such PUR systems often exhibit performancecharacteristics that are often superior to those of standard hot meltsadhesives.

In embodiments wherein the vent component sealing compositions comprisesa hot melt adhesive composition hermetic sealing is achieved by exposingthe sealable vent to any suitable heat source.

In certain preferred embodiments the vent component sealing compositionsis a hot melt adhesive composition that also comprises a suitable energyabsorbing material and the hermetic sealing is achieved by exposing thesealable vent to an induction heating source. In such embodiments theenergy absorbing material in the form of particles is admixed with thehot melt adhesive so that as the metallic particles are inductivelyheated adhesive melts. Useful energy absorbing materials for suchembodiments include, but are not limited to electrically conductingmetals, ceramics, carbon and the like as well as mixtures andcombinations thereof. Particularly useful metals for use in theseembodiments include, but are not limited to, iron, steel, aluminum,zinc, copper and silver as well as mixtures, combinations and alloysthereof. In certain other preferred embodiments the vent componentsealing compositions comprises a hot melt adhesive that is in intimatecontact with a porous metallic foil or film and the hermetic sealing isachieved by exposing the sealable vent to an induction heating source.In such embodiments the adhesive melts as the metallic foil or film isinductively heated. Particularly useful metals for use in the porousmetallic foil or film of these embodiments include, but are not limitedto, iron, steel, aluminum, titanium, zinc, copper and silver as well asmixtures, combinations and alloys thereof. Other energy absorbingmaterials useful as components of foils or coated films useful in thepresent invention include, but are not limited to, various forms ofelectrically carbon as well as electrically conducting ceramics such asindium tin oxide.

Induction heating sources with wide range of frequencies are availableand are useful in embodiments of the present invention. There is arelationship between the frequency of the RF field generated by theelectromagnetic induction source and the depth to which it penetrates amaterial; low frequencies (up to 30 kHz) are effective for thickermaterials requiring deep heat penetration, while higher frequencies (100kHz to >800 MHz) are effective for smaller parts or shallow penetration.In general, the higher the frequency the greater is the heating rate fora particular material, for example, a frequency particularly useful forinductive heating of iron particles such as microparticles ornanoparticles is 800±100 MHz.

In certain embodiments wherein the porous fusible sealing element isexternally activatable by an electromagnetic induction source operatingat a frequency ranging from 5 kHz to 100 GHz. In certain preferredembodiments the fusible sealing element is externally activatable by anelectromagnetic induction source operating at a frequency ranging from 5kHz to 900 MHz. In yet certain other preferred embodiments the fusiblesealing element is externally activatable by an electromagneticinduction source operating at a frequency ranging from 800 MHz to 100GHz.

A variety of radiant-curable adhesives, which are suitable for use asvent component sealing compositions in embodiments of the presentinvention, are currently used in a wide range of manufacturing processesand are commercially available. In general, such radiant-curableadhesives are solvent-free adhesives that are rapidly cured when exposedto radiant energy such as ultraviolet (UV) and electron beam (EB)systems. Suitable UV light-curable adhesive compositions may includephotoinitiators to activate the cure, wherein energy in the ultravioletrange of the spectrum (200-400 nm) is absorbed by the photoinitiators toachieve the rapid photochemical cure. Components of a UV light curingsystem generally include a light source that is usually a quartz lamp, apower supply, reflectors to focus or diffuse the light, cooling systemsto remove heat and a conveyor system. EB-cured adhesives, though similarin function and performance to UV light-curable adhesives, generally donot require the use of a photoinitiator. Instead, an electron beamwithin the equipment exposes the adhesive composition to low-energyelectrons, rapidly curing the composition. In general EB curing systeminclude a control panel, a transformer for voltage and an electronaccelerator. Radiant-curable adhesive compositions, which are suitablefor use as vent component sealing compositions in preferred embodimentsof the present invention, contain 100% solids and are volatiles-free.

In certain embodiments wherein the gas permeable vent component isdisposed within the container closure, the closure is secured to thecontainer body and the container is oriented during the filling processsuch that the container closure vent provides gaseous communicationbetween the headspace of the liquid filled container body and theexterior environment. In FIG. 1 is illustrated an isometric view of suchan embodiment wherein a sealable container 10 has a container body wall11 with a container opening 12 and a container closure in the form of acontainer cap 14, wherein the cap 14 is threadedly mated to thecontainer 10 at a threaded 500 container neck 13. A sealable gaspermeable vent component 15 is disposed within container cap 14.

In certain embodiments wherein the gas permeable vent component isdisposed within the wall of the container body, the sealable gaspermeable vent component is oriented such that it provides gaseouscommunication between the headspace (volume above the liquid level) of aliquid filled container body and the exterior environment. In suchembodiments the sealable gas permeable vent component may be locatedanywhere within the wall of the container body. In FIG. 2 is illustratedan isometric view of such an embodiment wherein a sealable container 20has a container body wall 21 with a container opening 22 and a containerclosure in the form of a threaded container cap 24, wherein the cap 24is threadedly mated to the container 20 at a threaded container neck 23.A sealable gas permeable vent component 25 is disposed within containerbody wall 21 which, when the container is utilized in a liquid hot-fillprocess, is oriented such that gaseous communication is provided betweenthe exterior environment and the headspace 26 above a liquid level 27 ofthe liquid filled container 20.

In certain embodiments of the gas permeable vent component an energyabsorbing material is dispersed therein or layered upon a porous matrixcomprising a fusible material. Upon application of a suitable energysource, such an energy absorbing material transfers energy in the formof heat to the fusible material, wherein the fusible material fuses(melts or softens) porous matrix becomes non-porous and effects hermeticsealing of the container. In certain preferred embodiments the energyabsorbing material contains a metal such as iron, steel, copper, silver,aluminum, titanium and zinc as well as alloys and mixtures thereof. Inother preferred embodiments the energy absorbing material containsvarious forms of carbon or electrically conductive ceramics including,but not limited to, indium tin oxide. In such embodiments the porousmatrix comprises a thermoplastic material and the energy source is anelectromagnetic induction source. Upon application of theelectromagnetic induction source the energy absorbing material isinductively heated to effect fusion of the thermoplastic material,wherein the pores of vent component are sealed through melt bondingand/or capillary filling. In certain embodiments the energy absorbingmaterial comprises particles ranging from macroparticles tomicroparticles, which are incorporated into the thermoplastic material.In certain other embodiments the porous matrix of a container vent has alaminate structure comprising one or more fusible porous layers adjacentto one or more non-fusible porous layers. Alternately such a laminatestructure comprises one or more first fusible porous layers adjacent toone or more second porous layers wherein the second porous layercomprises a fusible material with a melting point higher that that ifthe first fusible porous layer. In such systems hermetic sealing of thevent is achieved by the intrusion of a fusible porous layers into thepores of adjacent non-fusible or higher melting layer.

Certain preferred embodiments of the sealable gas permeable vents of thepresent invention utilize a laminate structure comprising a first porousmatrix, a porous metallic foil or film, a thermoplastic material and asecond porous matrix. In a hot-fill process the porous metal foil isinductively heated wherein the thermoplastic intrudes into the pores ofthe porous metal foil and the second porous matrix resulting in ahermetic seal. One such embodiment is presented in FIG. 3 depicting asectional front orthogonal view of a threaded container cap 30 having asealable gas permeable vent component fixedly disposed within. In thisembodiment the sealable gas permeable vent component has a laminatestructure comprising a first porous matrix 31 in intimate contact withone surface of a porous thermoplastic sealing composition layer 33,while the opposite surface of the porous thermoplastic sealingcomposition layer 33 is in contact with one surface of a porous metallicfoil or film 34 and the opposite surface of the porous metal foil 34 iscontact with a second porous matrix 32. When utilized in a hot-fillprocess, the container is filled with liquid and the metal foil or film34 is inductively heated by a suitable induction means until thethermoplastic sealing composition layer 33 sufficiently softens ormelts, coalesces and flows through the pores of the porous metallic foilor film 34 and into the pores of the second porous matrix 32 to a depthsufficient to produce a hermetic seal. In such a process the softened ormolten thermoplastic material 33 may also flow into the pores of thefirst porous matrix 31.

Another such embodiment is presented in FIG. 4 depicting a sectionalfront orthogonal view of a threaded container cap 40 having a sealablegas permeable vent component fixedly disposed within. In this embodimentthe sealable gas permeable vent component has a laminate structurecomprising a first porous matrix 41 in intimate contact with one surfaceof a porous metallic foil or film 44 while the opposite surface of theporous metallic foil or film 44 is in contact with one surface of aporous thermoplastic layer 43 and the opposite surface of the porousthermoplastic layer 43 is contact with a second porous matrix 42. Whenutilized in a hot-fill process, the container is filled with liquid andthe metallic foil or film 44 is inductively heated by a suitableinduction means until the thermoplastic material 43 sufficiently softensor melts, coalesces and flows through the pores of the porous metallicfoil or film 44 and into the pores of the second porous matrix 42 to adepth sufficient to produce a hermetic seal. In such a process thesoftened or molten thermoplastic material 43 may also flow into thepores of the first porous matrix 41. Yet another such embodiment ispresented in FIG. 5 depicting a sectional front orthogonal view of athreaded container cap 50 having a sealable gas permeable vent componentfixedly disposed within. In this embodiment the sealable gas permeablevent component has a laminate structure comprising a first porous matrix51 in intimate contact with one surface of a first porous metallic foilor film 54 while the opposite surface of the first porous metallic foilor film 54 is in contact with one surface of porous thermoplastic layer53, the opposite surface of porous thermoplastic layer 53 is in intimatecontact with a surface of a second porous metallic foil or film 55 andthe opposite surface of porous metallic foil or film 55 is in intimatecontact with a second porous matrix 52. When utilized in a hot-fillprocess, the container is filled with liquid and the metallic foil orfilm 54 and/or the metallic foil or film 55 is inductively heated by asuitable induction means until the thermoplastic material 53sufficiently softens or melts, coalesces and flows through the pores ofthe porous metallic foil or film 54 and/or the metallic foil or film 55and into the pores of the first porous matrix 51 and/or second porousmatrix 52.

In FIG. 6 is depicted an embodiment wherein a sealable gas permeablevent component 60, comprising a porous sealing layer 62 disposed betweena first porous matrix 63 and a second porous matrix 64, is fixedlydisposed within container body wall 61. In certain preferredembodiments, the sealing layer 62 comprises a porous thermoplastic,while in other preferred embodiments the sealing layer 62 comprises aporous radiant-curable adhesive.

In FIG. 7 is depicted an embodiment wherein a sealable gas permeablevent component 70, comprising a porous sealing layer 74 disposed betweena first porous matrix 72 and a second porous matrix 73, is fixedlydisposed within container body wall 71. In such embodiments, the poroussealing layer 74 is a thermoplastic material that contains an energyabsorbing material such as a metal, ceramic or carbon in form ofparticles 75 dispersed throughout and wherein inductive heating effectshermetic seal.

In FIG. 8A is depicted a sectional frontal orthographic view of aembodiment of the present invention wherein a sealable vent componentcomprising a laminate structure comprising a first porous matrix 81 inintimate contact with one surface of a porous metallic foil or film 83while the opposite surface of the porous metallic foil or film 83 is incontact with one surface of a porous thermoplastic sealing compositionlayer 84 and the opposite surface of the porous thermoplastic layer 84is contact with a second porous matrix 82. Wherein the sealable ventcomponent is disposed within a threaded container cap 80 positionedwithin the range of an induction heating means 85 at the onset of asealing process. In FIG. 8B is depicted the sealable vent component capassembly of FIG. 8A after the induction heating sealing process whereinthe thermoplastic sealing composition layer 86 has been sufficientlysoftened or melted to produce a hermetic seal.

In certain embodiments of the present invention the sealable ventcomprises an externally activatable porous vent sealing composition inthe form of a ring that is sized and positioned within a threadedcontainer cap such that it is in contact with the interior top surfaceand interior annular surface of the container cap. When this containercap is threadedly secured to the neck of a mated container the ring isin intimate contact with the top surface of a threaded container neck.In such embodiments the threads of the container cap and the containerneck are sized such that when the cap is secured to the container thereis a sufficient thread gap between the cap threads and container neckthreads to permit gaseous communication from the interior of thecontainer through the porous sealing ring and through the thread gap tothe exterior environment. When used in a hot fill process the containeris filled with hot liquid; liquid in container is allowed to cool,during which time the pressure within the container and the externalenvironment equilibrates; and the externally activating the vent sealingcomposition by non-mechanical means to effect hermetic sealing of thecontainer cap to the container neck. In effect the annular porousvent-sealing element is transformed into a circular gasket or O-ringupon application of a suitable external activation means. As in otherembodiments of the sealable vents of the present invention the porousvent sealing composition comprises a thermoplastic material such as ahot-melt adhesive, which in some embodiments may contain an energyabsorbing material such as a metal, ceramic or carbon, and the externalactivation means is an induction heating means. As in certain otherembodiments the energy absorbing material can be in form of particlesdispersed throughout the porous fusible material. In yet otherembodiments the energy absorbing material comprises a metal or metallicporous foil or metal coated film, which is disposed above the in the topof the cap and above the ring and is in intimate contact with theannular porous vent-sealing element. In other embodiments of the annularporous vent sealing composition comprises a radiant-curable adhesive andthe external activation 670 means is a radiant energy source such asultraviolet (UV) light or an electron beam (EB). In embodiments whereinradiant energy is utilized the container cap is fabricated frommaterials that are transparent to the required radiant energy.

Depicted in FIG. 9 is an isometric view of an embodiment wherein athreaded container cap 90 is threadedly secured to a container 91 andwherein a porous vent sealing composition in the form of a ring 92 isdisposed within the cap 90. Depicted in FIG. 10 is a sectionalorthogonal frontal view of the container cap 90 threadedly secured tocontainer 91, which illustrates the relationship between the poroussealing ring 92, the cap 90 and the threaded neck 93 of the container91. Also illustrated in FIG. 10 is a thread gap 94, a container neck lip95 and a vent space 96, which form a gaseous vent path defined by therelative sized and geometries of the porous sealing ring 92, the cap 90and the threaded neck 93. When used in a hot fill process the container91 is filled with hot liquid; liquid in container is allowed to cool,during which time the pressure within the container and the externalenvironment equilibrates by the gaseous communication through the pathdefined by the vent space 96, the porous sealing ring 92, and the threadgap 94; after which the porous sealing ring 92 is externally activatedwherein it is rendered non-porous and effects hermetic sealing of thecontainer.

In certain other embodiments of the present invention the sealablecontainer comprises a container body formed by a container wall definingan interior space and an exterior environment, wherein the containerbody comprises a threaded closable opening; a threaded container caphaving interior top surface and interior annular surface wherein thethreaded container cap is mated to the threaded closable opening; and agas permeable vent in the form of a ring sized and positioned within thethreaded container cap such that it is in contact with the interior topsurface and interior annular surface of the container cap, wherein thegas permeable vent comprises a hot-melt adhesive vent sealingcomposition that is externally activatable by radiative means to effecthermetic sealing and wherein the container cap has a layer of metallicfoil or film disposed between the container cap interior top surface andthe gas permeable vent such that the metallic foil or film maintainsintimate contact with the interior top surface of the container cap andwith the vent sealing composition of the gas permeable vent. In certainpreferred embodiments the gas permeable vent in the form of a ringcomprises a bi-layer structure having a non-fusible porous layer and avent material and an externally activatable vent sealing compositionlayer in intimate contact. In FIG. 11 is depicted an exploded isometricview of such an embodiment wherein the container cap assembly 100consists of a threaded cap shell 102, in which is disposed a disk ofmetallic foil or film 103, a gas permeable vent externally activatablevent sealing element in the form of a ring 104 and an optionalnon-externally activatable gas permeable vent element in the form of aring 105. In FIG. 12 is depicted a sectional frontal orthogonal view ofthe same embodiment illustrated by FIG. 11 wherein the container cap 100is threadedly fixed to the container body 101. FIG. 12 clearlyillustrates the relationship between the threaded cap shell 102, thedisk of metallic foil or film 103, the gas permeable vent externallyactivatable vent sealing ring 104 and a non-externally activatable gaspermeable vent ring 105. When such an embodiments is utilized in a hotfill process the container body 101 is filled with hot liquid; liquid incontainer is then allowed to cool, during which time the pressure withinthe container and the external environment equilibrates by the gaseouscommunication through the path defined by the vent space 109, the poroussealing ring assembly consisting of activatable vent ring 104 andnonactivatable vent ring 105, and the thread gap 108; after which thecap is exposed to an induction heating means wherein the disk ofmetallic foil 103 is inductively heated to soften or melt theactivatable porous sealing ring 104 wherein it is rendered non-porousand effects hermetic sealing of the container. Although the inventionhas been disclosed in the context of certain embodiments and examples,it will be understood by those skilled in the art that the inventionextends beyond the specifically disclosed embodiments and examples toother alternative embodiments and/or uses as well as obviousmodifications and equivalents thereof.

We claim:
 1. A method for hot-filling and sealing a container comprisingthe steps of: i. providing a container comprising: a container bodyformed by a container wall defining an interior space and an exteriorenvironment; wherein the container body comprises a closable opening, acontainer closure mated to the closable opening and a gas permeable ventcomponent, comprising a porous material providing gaseous communicationbetween the interior space of the container body and the exteriorenvironment, wherein the vent component further comprises a ventcomponent sealing composition and an energy absorbing layer that isexternally activatable by an electromagnetic induction source to effecthermetic sealing; ii. filling the container with hot liquid; iii.allowing the hot liquid to cool; and iv. externally activating theenergy absorbing layer with the electromagnetic induction source toeffect hermetic sealing.
 2. The method of claim 1 wherein the gaspermeable vent component is disposed within the container closure. 3.The method of claim 1 wherein the gas permeable vent component isdisposed within in the container wall.
 4. The method of claim 1 whereinthe porous material comprises a porous membrane.
 5. The method of claim1 wherein the porous material comprises a polymer.
 6. The method ofclaim 1 wherein the porous material has a pore diameter in the range of0.01 μm to 350 μm.
 7. The method of claim 1 wherein the porous materialhas a pore diameter in the range of 5 μm to 40 μm.
 8. The method ofclaim 1 wherein the vent component sealing composition comprises aporous fusible material.
 9. The sealable container of claim 8 whereinthe porous fusible material is a thermoplastic.
 10. The method of claim9 wherein the thermoplastic is a hot-melt adhesive.
 11. The method ofclaim 8 wherein the gas permeable vent component further comprises anon-fusible porous matrix or membrane disposed directly above or belowand in intimate contact with the porous fusible material.
 12. The methodof claim 8 wherein the vent component further comprises an energyabsorbing layer.
 13. The method of claim 1 wherein the vent componenthas a laminate structure comprising a first porous matrix and a secondporous matrix, wherein the vent component sealing composition isinterposed there between.
 14. The method of claim 1 wherein theelectromagnetic induction source has a frequency from 5 kHz to 100 GHz.15. The method of claim 1 wherein the electromagnetic induction sourcehas a frequency from 800 MHz to 900 MHz.
 16. The method of claim 1wherein the porous material comprises a first porous matrix, the ventcomponent sealing composition comprises a second porous matrix andwherein the vent component has a laminate structure comprising the firstporous matrix, the second porous matrix and a porous metal foil disposedthere between such that the first porous matrix and the second porousmatrix maintain intimate contact with the porous metallic foil.
 17. Amethod for hot-filling and sealing a container comprising the steps of:i. providing a container comprising: a container body formed by acontainer wall defining an interior space and an exterior environment;wherein the container body comprises a threaded closable opening, athreaded container cap having interior top surface and interior annularsurface wherein the threaded container cap is mated to the closableopening; and a gas permeable vent in the form of a ring sized andpositioned within the threaded container cap such that it is in contactwith the interior top surface and interior annular surface of thecontainer cap, wherein the gas permeable vent comprises a porousmaterial and a vent sealing composition and an energy absorbing layerthat is externally activatable by an electromagnetic induction source toeffect hermetic sealing; ii. filling the container with hot liquid; iii.allowing the hot liquid to cool; and iv. externally activating theenergy absorbing layer with the electromagnetic induction source toeffect hermetic sealing.
 18. The method of claim 17 wherein the ventsealing composition comprises a hot-melt adhesive.
 19. The method ofclaim 17 wherein the container further comprises a layer of metallicfoil or film disposed within the threaded container cap between theinterior top surface and the gas permeable vent such that the metallicfoil or film maintains in intimate contact with the interior top surfaceof the container cap and with the vent sealing composition of the gaspermeable vent.
 20. A method for hot-filling and sealing a containercomprising the steps of: i. providing a container comprising: acontainer body formed by a container wall defining an interior space andan exterior environment; wherein the container body comprises a closableopening, a container closure mated to the closable opening and a gaspermeable vent component, comprising a porous material providing gaseouscommunication between the interior space of the container body and theexterior environment; wherein the vent component further comprises avent component sealing composition and an energy absorbing material inthe form of particles dispersed throughout the sealing composition, suchthat the sealing composition is externally activatable by anelectromagnetic induction source to effect hermetic sealing. ii. fillingthe container with hot liquid; iii. allowing the hot liquid to cool; andiv. externally activating the energy absorbing material with theelectromagnetic induction source to effect hermetic sealing.
 21. Themethod of claim 20 wherein the gas permeable vent component is disposedwithin the container closure.
 22. The method of claim 20 wherein the gaspermeable vent component is disposed within in the container wall.
 23. Amethod for hot-filling and sealing a container comprising the steps of:i. providing a container comprising: a container body formed by acontainer wall defining an interior space and an exterior environment;wherein the container body comprises a threaded closable opening, athreaded container cap having interior top surface and interior annularsurface wherein the threaded container cap is mated to the closableopening; and a gas permeable vent in the form of a ring sized andpositioned within the threaded container cap such that it is in contactwith the interior top surface and interior annular surface of thecontainer cap, wherein the gas permeable vent comprises a porousmaterial, a vent sealing composition and an energy absorbing material inthe form of particles dispersed throughout sealing composition such thatthe vent sealing composition is externally activatable by anelectromagnetic induction source to effect hermetic sealing ii. fillingthe container with hot liquid; iii. allowing the hot liquid to cool; andiv. externally activating the energy absorbing material with theelectromagnetic induction source to effect hermetic sealing.